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To ALLWHOM ITv MAY CONCERN: I

Be it known that I, VILLIAM REYNOLDS, of Columbia, in the county of'Richland, and State of South Carolina, have invented a new and improved Mode of ConstructingAI-ticial Dentures (sets of teeth) on vulcanite' rubber or moulded vmetallic base; and I do herebyr declare that the following is-a'full and exact description thereof, reference being had to the accompanying drawings, and tothe letters of reference markedthercon.

The nature of my invention or improvement consists in socori'structing sets "ofteeth on mouldedbase (hard rubber, for example,) that they shall possess, in a high degree, several `advantages pertaining to swaged metallic plates, viz, durability, less bulk, a slight degree of elasticity, with great facility of repair.

To this end, instead of resorting' to the use of teeth so frail as those specially designed for vulcanite base,

Isu'bstitute single metallic-plate teeth, on account of their greater strength, facility Cif-replacement in case of accident, and the opportunity afforded of dcparting,-in their arrangement, from the' regularity and 'sameness of the former. In regard to incisors and canines especially, theiatter are more characteristic.

These teeth I attach to a thin bar, a, of gold, or other suitablomctal, ranging yalong and near the base of. 'the teeth on' their inner side, by means cfa tapering elongation, b, of the same piece of plate which formsthe backing, and which is to be riveted upon this bar, as shown in' the drawings. To render the riveting of these elcngations upon the bar more easy, they are, before beingriveted to the teeth, to be reduced from the point of departure, at the base of the teeth, to the extreme end, Aat least one-third in thickness.. Thisl thinning is most expeditiously effected by biting between rollers the cud of aipiec'e of plate, of suiiicient length to line an entire set, or it may be done by pinning out-each piece separately. In either case` annealing becomes necessary before riveting, unless in eases where feebleness of the platinum pins suggests the propriety of soldering, which becomes seldom necessary with teeth of approved modern manufacture, A hole or two punched through these eXtensions, and reamed near the base of the teeth, permits of union of the rubber below with whatcver'may be above them, thus formingrivets, and serving as such, should the upper surface be so reduced in nishing theset as to uncover the metal. A semi-lunarA notch along the sides 'of these extensions admits more vulcanite rubber between them, and renders them easily turned upon the bard A hole punched through near the extremity of the extension facilitates the turning over upon-,the bar` These extensions are also to be bove'lled along the edges,'formore effectual resistance to accidental downward force. Teeth, particularly incisors and canines, acquire, when thus attached to a rigid base, a degree of saliency, which, however slight, enables them to maintain their integrity against a force which would fracture or dislodge vulcanite or cheoplastic` teeth. By this method, it will be observed that the porcelain is shielded from undue pressure. Wherever this falls upon a tooth, it is rst received upon the metal backingand extended attachment, and there eXpendedS-a result to which is mainly attributable the great durability of gold-plate work, often to tbe met with, doingv goed service over a period of twenty years. The bar to which these elongations of the backingsj'are attached fulfills other very important relations to the plate and teeth. It effectually prevents vfractures from originatingoit the anterior and lateral portions of the plate, and retains the teeth attached to itin theirtrue positionnnder.the'spreading pressureto which they become subjected on the final screwing up of theilask. i

As a genera-l rule, full sets of teeth on a moulded base are moredesirable toV practitioners than partial cases, on account of their greater strength, and the liability of the latter tobe'come fractured where the continuity of the arch is interrupted by openings for natural teeth to passrthrough.. Hence arises the deplorable .but too cpnimon practice, of a certain class of operators, of removing whatsoever teeth stand inthe way cfa full set, without much regard to number, or the practicability of saving them; This bar will be found so to strengthen partial sets, by embracing all openings encountered in its course, that thepractice just referred to may, by its adoption, be greatly mitigated. 1

In combination with this bar, which so eiiectua-lly protects the anterior portion and sides of thegplate from fracture, I adapt, near to the posterior edge, and along its course, to such au extcntas may be deemed necessary, a thin strip of gold or otherv metal plate, c, suitable for the purpose, which, producing an eiieet similar to that produced by the bar in front, precludes the possibility of fracture originating there. This strip is readily brought into its proper position on the model by slightly pinning the anterior edge on the beak of a small anvil,-

and afterwards annealing. Two points, 1 2, are to bc formed at each end by notching deeply with a thin ile.

4One of these points turned upward will be embedded in and form a permanent attachment to the plate; the

other, turned downwards, serves as a temporary hold to the model when the sheet of rubber is laid upon it.

No packing of rubber is required, except a thin slip under the bar, and an additional strip above the extensions of the backings, before the full sheet is laid on. Under the posterior metnl strip no vulcanite rubber need be placed, nor under an anterior one, d, when used, the intention being that they shall appear on the lingual surface ofthe plate when finished. In addition to the hold given by the bent points at each end of the strips, the edges should be bevelled, for greater security, and, if deemed necessary, they may, by punching a few holes, 2 3 4, and reaming these, cause the rubber to formrivets along their whole length. Vulcanite teeth may be attached to their base by this method as securely as plate-teeth, but their liability to fracture remains the same, unprotected, as they would still be, by the absence of metal backing.

The admirable adaptation of this method to under sets needs' not to be enlarged upon. The mode of construeting them, and loading with a bar of block-tin, (the best material for thus loading is fully shown in tig. 2. For partial lower cases, as Where the front teeth and canines remain, the rest being lost, this method greatly multiplies the probabilities of succeeding in affording comfortable case. The bar passing from one 4side to the other, behind the natural teeth, and attached, as above described, to thenrtiiicial teeth on each side, whilst adding vastly to the strength, obviates the encroachment which the tongue experiences from moulded plates, which of necessity have to be cumbersome at this point.

For all the purposes where metal. is used, (except the tin bur for under sets,) gold is to be preferred. Silver is too easily destroyed in vuleanizing to be admissible. Platinum is too soft. Aluminium or its compounds may be found to answer; or any other-metals of sufficient strength,when rendered thin enough for the purpose r and for use in the human mouth, are not objectionable.

Besides the bar c, another bar, d, similar in all respects, may be made use of, and, when employed, should be placed more ton-ard the front or the plate, for 'its better protection in cases where the bar, adapted to metallic backs, is dispensed with, and teeth designed for moulded-plate work are used.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is 1. The bar a, formed of gold or other suitable metal, adapted for the prevention of fractures in the anterior and lateral portions of the plates, and as an attachment for the teeth, substantially as described.

2. The thinned extension b ofthe backing, of form and mode of adaptation to the bar, as herein described and shown.

i WM. REYNOLDS.

Witnesses:

W. F. DE SAUssUns, JOHN M. MILLER. 

